Apparatus and method for measuring Internal Ocular Pressure (IOP) comprises applying a perturbing vibration into an eye over a range of frequencies. A vibrational response of the surface of the eye is measured such as by using a laser velocimeter, the vibrational response including velocity and rate of change of the phase lag. Further, geometric properties such as volume of the eye are measured such as by using a laser interferometer to measure characteristics such as the eye's axial length and cornea thickness. Use of multiple characteristics normalizes the effect of an eye's mechanical and geometric properties and thereby more accurately determines the IOP.